Heat exchanging apparatus



L. B. SCHIBBYE HEAT EXGHANGING APEARATUS Filed' Jag. 28. 1944 Sept. 21,`194s.

msg 4 Patented Sept. 2.1,

man:` EXCHANGING APPARATUS Laurita Benedictus Schlbbye, Essvik, Sweden,ase l I signor to Svenska Cellulosa Aktiebolaget, Stock- `holm, Sweden,a company of Sweden Application January 28, 194e, vSerial No.

' In Sweden December 11, 1942 1 claim. (ol. 25a- 229) The presentinvention relates to a heat exychanger of the type in which the mediumsbetween which the heat transfer isto take place. are subiected tohelical or spiral motion. As a rule, heat exchangers of this ltype givea high eillciency, but the embodiments hithertoknown have certain in'herent disadvantages and limitations. Thus, they are not suitable formediums which yield deposits in the form of incrustations, soot or thelike. They Vare diillcult to repair and the joints and connections arediillcult 4to pack so as to be' perfectly tight.

The primary object of the 4present invention is to provide a heatexchanger of the abovemen- .tioned :type by means of which thesedisadvantages are eliminated or at least considerably reduced. A mainfeature of the invention is that it includes -a casing or tube -and abody therein, the body having a substantially helical internal passage(or passage system) for one medium and yproviding a substantiallyhelical external passage (or passage system) for another medium.

An object of the invention is to further improve the heat transfer fromone medium to the other by avoiding the double walls in the path alongwhich the heat transfer takes place.

Another object is to provide a large cross-sectional area particularlyfor the external passage so that a great speed throughjthe exchanger canbe given to the medium flowing through the said passage, particularly ifit is a gas. This can be done by providing two or more helical ducts andby giving one of lthe passages a cross-sectional area which is at leasttwice as large as that of the other.

A further object is to'provide a heat exchanger which is easy todisassemble, in order to externally clean the inset body and internallyclean the casing or the tube. With such a heat exchanger it is onlynecessary to avoid the use of a medium and comprising three helical orspiral coilsA threaded one into the other. I

Fig. 2 is a'sectlon of the apparatus online II-II of Fig. 1. A

VFig.I 3 is a longitudinal section of part of another embodiment inwhich Ithe interior body is :a single coil.

Fig. 4 is a similar section of an apparatus with a single coll and of amodiiled embodiment of the Itwo halves as will be seen from IFlg. 2, andhav# ing the detachable cover 2 and the detachable bottom 3. Near itsupper end the casing has a flange tube 4 for the connection of a pipeline, and near its lower end .there is a similar flange tube 5. Thecasing encloses three fiat hollow coils I6, T, 8 screwed into oneanother. Therst coil is fixed to an axial center tube 9 forming the coreof the coil body, while the other coils 1, 9 are not at- .tached to thecenter tube and may be screwed into lthe rstmentloned coil. The threeconduits thus obtained are connected to an upper header I3 by means ofsuitable end portions I0, I I, I2, see also Fig. 2. By means of a neck`I4 this header communicates with an opening I5 in the cover 2.

At the bottom the conduits have similar radial end portions I'B, I'I, I8connected to a lowerI header I9 in the casing I. Through a neck 20 thisheader communicates with an opening 2l in the bottom 3 and an extrachamber 22 with an opening 23, the said chamber being situated below.the said header I9.

The exchanger described operates in the following manner:

One of the mediums participating in the. heat exchange is admitted, forexam-ple, through the opening 23, ypasses ,through the chamber 22 and aheat exchanger embodying the invention, the

interior body being shown generally in elevation enters lthe lowerheaderI9 from which the me- -dium is distributed to the three conduits 8, 1, Ithrough the connections IIS, I1, I8. HavingI passed the said conduitsthe medium, vla the connections I0, II, I2, enters the upper header I3which thus forms an outlet header for the different medium currents,from which header the collected medium leaves through the opening I 5and a pipeline connected thereto, not shown. i

-The second medium is admitted for example through the flange tube I andthus enters the casing I in which the medium passes vthrough theintermediate spaces between .the convolutions of the openings ormanholes.

-what exaggerated in Fig. 1.

andasse coils 6, '8. This medium then leaves through the flange tube 5.Y

Both of the mediums are forced to pass a long distance 4through theapparatus and in suitably thin layers, and therefore the heat exchangebecomes efllcient even in an apparatus of moderate dimenstions.

In order to clean the apparatus. the two parts of the casing are takenapart after the cover and/or the bottom have been removed.

If desired, the casing may be made up of a plurality of sectional wallelements or parts in such a way that only one or more parts need beremoved pipes and the liquid inside thereof. Further,

for the cleaning of the interior of the casing and the exterior of theconduits. The said part or parts may preferably have the form ofcleanout The connection between the header I3 and the cover may be suchthat the header and the coils can be lifted from the casing by raisingthe cover.

The cover, the bottom and the remaining parts of the casing may -bedesigned, as to material and thickness thereof, for adequate strength topermit -a substantial pressure on the medium flowing .through thepassage or passages on the outside of the inset body, and the pressureon the-medium flowing through the conduit or conduits of the inset bodymay then be substantially higher, for any given strength of the wall-sof the inset body. than would be practical in the absence of asubstantial pressure at the exterior of the inset body.

Thecoils may extend to .the wall of the casing or, in order tocompensate for unequal expansion, may end at some distance therefrom asis some- Through the intermediate spaces impurities which by thecentrifu gal force of the spiral motion are thrown toward-s the wall ofthe casing, sink downwards and may be removed from the lower portion ofthe casing. To facilitate the. separation and removal of the impuritiesthe wall of the casing may be provided with grooved bulges runningparallel with the intermediate `spacesbetween the winding convolu tions,as indicated at in Fig. 4. Only one helical or spiral coil is shown inthis figure. The said coil is made without a core. Moreover, there maybe any number of coils in the same'casing. The said grooves 25 in whichthe heavy impuri-ties gather, may be vprovided with cleaning openings orblow-out pipes at suitable points.

As indicated in Fig. 3, inspection glasses 26 are provided wherenecessary, to permit observation of the interior of the exchanger.

Itis to be noted that the invention is vnot lim-v itecl to a particularshape or geometry of the heat exchanger and that it may be embodied inapthe passage area of the external pass-age should preferably diminishin .the ow direction of .the gas corresponding about to the volumereduction of the gas caused bythe fall of temperature. This ter. vOfcourse, the case will be the reverse if the heat absorbing medium thevolume of whichincreases in the flow direction, passes around the coils.The main point is that the passage area decreases or increases accordingto the volume change of the medium in the ow direction.

Having now ldescribed my invention, what I claim as new and desire tosecure by Letters Patent 1S: y o

A heat exchanger comprising a substantially cylindrical shell, aplurality of conduits Within saidv shell, each conduitl being in theform of a substantially right helicoid and said helicoids -beingconcentric and of equal size and pitch land the turns thereof beingequally spaced from each other thereby forming -a plurality ofhelicoidal 'passageways of substantiallyuniform cross-sec- `tional shapethrough said cylindrical shell. the

paratus of other form than the illustrated embodiments in whichthecasing has -a cylindrical shape, and the outer periphery of the coilslies in a cylindrical surface.

When heat is transferred from gases to a liquid, from exhaust gases o rwater vapor to water, for example, it is suitable to permit thegas orgases to pass outside of the convolutions of the pipe or cross-sectionof each conduit as cut by a plane 'through the axis of the cylinderbeing substantialhr rectangular and -the dimension of said crosssectionperpendicular to the axis of .the cylinder being substantially equal ltothe' radius of the cylind-rical shell and at least several times thedimension of the cross-section of the conduit parallel to the axis ofthe cylindrical shell, means for passing a fluid through said conduitsand means for passing another fluid through said passage- Ways.

LAURITZ BENEDICTUS SCHIBBYE.

REFERENCES orrnn Thel following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name y Date n 205,153 Tregent June 18, 1878410,287 Kuhn Sept. 3, 1889 441,371 Morrell Nov. 25, 1890 A 851,985Goldfein Apr. 30, 1907 1,280,656 Buhr Oct. 8, 1918 1,621,374 McPhee Mar.15, 1927 1,725,549 Swenson Aug. 20, 1929 1,799,039 Conejos Mar. 31, 19311,852,489 Sullivan Apr. 5, 1932 1,852,490 Sullivan Apr. 5, 19321,868,271 Boehm July 19, 1932 1,892,778 Bla-ck Jan. 3, -1933 1,985,785Kellogg Dec. 25, 1934 2,012,920 Summerfield Aug. 27, 1935 FOREIGNPATENTS Number Country Date 29,061 Great Britain Dec. 16, 1913

